It is well known that disturbances in the blood circulation in limbs causes the temperature of the skin to deviate from normal values. This fact has been utilized in diagnosing the aforementioned disorders in circulation, IR-scanning cameras being used to this end. Such cameras, however, are expensive and are relatively complicated in use, and hence a more comprehensive use of IR-scanning cameras for detecting and diagnosing disturbances in circulation by thermography is hardly conceivable.